Just make sure you use a Craftsman model 1019 Laboratory Edition Signature Series torque wrench. (The kind used by Caltech high energy physicists. And NASA engineers.) And routinely twist the maximum allowable torquage.

 

Also the ARP stud set is re-usable as they do not stretch to yield like the LR bolts. So they might cost more up front; but its a one time purchase.

 

In case anyone is interested, here's where I posted the info I got from the person at Boltscience:
Single use head bolts vs studs

 

Stretch bolts do not require the head to slip on the aluminum to attain proper clamping force, the extra torque is put on your arm to spin the bolt, not on the clamping force of the fastener.

On the other hand, ARP studs require VERY SPECIFIC lubricant and extremely precise torque measurement to get clamping force delta within reason. With ARP you are not torquing the bolt to yield to give an engineered clamping force, you are actually clamping the head tighter or looser with every 1/16 of a turn. What you can do to maximize accuracy is measure the angle between the 2nd and final torque by angle, and bring all the bolts up to the angle of the head bolt that turned the most, thus eliminating false readings from parasitic drag in the threads and nut-to-aluminum interference. I know this sounds like nonsense, but it is imperative that clamping force between 2 pieces of machined aluminum be equal across a gasketed surface that is as long as a V8 head.

You have to remember that ARP is unforgiving, every 1/16 of a turn can change clamping force by hundreds of lbs.

 

I don't think it matters that ARP studs are reusable.
From what Masterrovertech says - you put them in and mess up on the angles - and
you have problems.

The stretch bolts are more forgiving. And for the backyard / parking lot mechanic like me then I'll stick with them.

Let the precise mechanics worry about re-using the ARP studs and making them all exactly the same clamping force.

I guess all of you in the trade have a 6th sense about replacing head gaskets and that's learned, aquired and earned.

And, thanks for sharing!

 

With the ARP suds, you are to use a hardened washer under the nut. There is no direct contact with the aluminum. Torque is more accurate and no gouging due to the surface of the nut and hardened washer. Not sure how much more accuracy can be had when a torque wrench can measure in 2 ft pound increments on today's models. Heck, my old Snap-on with a dial is more than adequate for accurate readings. All that we are doing is stretching the stud/bolt to about .002 to hold tension. A bit more complicated at times, but studs are simple to use and have consistent clamping forces when used properly. Your over-thinking this way to much. I've used ARP studs on 4.6 caddy rebuilds many times, as well as the 1400 HP Alky tractor. On my LR with La Sleeves, I reused the original stretch bolts without fail. Bottom line is the Land Rover design is junk.

MAK

 

Even a brand new Snap-on torque wrench is only +/- 4%.

It's not a Land Rover design. Torque angle single use head bolts are probably the most common head fastener today, across all brands because they provide the most accurate/even clamping force.

 

Even with +/- 4% your torque specs are accurately off, so clamping pressure is consistent no matter. I don't buy into this at all. 4% of 70 pounds equates to 2.8 ft lbs. I'd be concerned about other aspects of the junk design such as the fire ring position and liner seating on the register.

It certainly is a LR design flaw, in that slipped liners and head gasket failure could have been eliminated considerably with the technology of the time. How many other engines have head gasket failure where it is recommended that one replaces these items as normal maintenance? I say bullcrap.

Should I use TTY bolts on our blown Alky puller instead of the ARP studs? Don't make me laugh to much.

MAk

 

"It's not a Land Rover design. Torque angle single use head bolts are probably the most common head fastener today, across all brands because they provide the most accurate/even clamping force." Back in the 1960s, I did a lot of automotive work, including rebuilding many engines, so I was stunned, when in the early 1990s, in working on my Range Rover 3.5 litre, when I was told to use the newer stretch head bolts, one time use bolts. Also, I was told by that extremely experienced engine re builder that stretch bolts are now common for most all engines. Obviously, Automotive engineers deemed them better, everything considered, so it is wise for us all to conform to that proposition, even those of us who have difficulty accepting change, such as myself.

 

Stretch bolts provide a clamping force that is more likely to be sustained than a stud. The bolts are fabricated to a specific cross section so that they will begin to experience plastic (non-recoverable) deformation above a certain torque. Once you stretch the bolts elastically by achieving tension within the bolt from the initial torque, you then elongate them in the plastic range by turning them a specific amount. The pitch of the thread determines how much they stretch as they are rotated. By moving the bolts into the range of plastic deformation, you have a tensile stress locked into the bolt that will be effective even if the dimensions between the head and the threads changes slightly. A stud that is more robust and experiences much less elongation when the nut is torqued will provide much less clamping force if there are any dimensional changes in what is being clamped. We use the same principle when installing a free-stress (unbonded) length in rock and soil anchors. When you pre-load the anchor you stretch the unbonded length. If the system experiences a little movement, there will still be a tensile force in the anchor.

The problem is that the Rover block is aluminum and the area where the threads are located is not thick enough to handle the loads imposed on it. Add the stress of a fastener being rotated while being loaded and you may eventually end up with cracks or just yanking the threads out during assembly.

The ideal solution would be stretch studs. If they can work 3 times, that should be enough. After the 2nd set of head gaskets it's time to get a new motor.